shaggybaxter said..JonE said..
I'm on my second RS422/485 usb converter. Bought the isolated one this time. Taking NMEA from the H3000 and the A+T MFD but I cannot get meaningful NMEA data no matter what I do..
Just to clarify, you are only trying to receive (listen) from a single transmitterr (talker), correct?
When I reread your post it sounds like you have two talkers transmitting to one listener, (which definitely wouldn't work).
Correct. The H3000 has NMEA out. The a+t also has it. I've tried both, with 2 different usb rs422 dongles (including an isolated one) and straight into serial on the pi. The baud rate is correct (4800) and I get the identical results from both bits of equipment.
tried with laptop and pi
I've tried powering the pi with a Buck converter from the boat's power same results.
If I had to guess, by looking at the data, I would say the data is inverted, but switching the pins gives no data at all so that's not the fix.
Edit: sorry, just read your first post. I don't have the cables for the serial or usb ports on the h3000 - I think if I did I would be off to the races. I'm using the NMEA Out port which is on regardless of jumper position.
if I could get the cable for usb or serial I would be very happy!
If the NMEA port is RS232 that could explain it, but then very interesting that the A+T is the same?